Among the saints commemorated on the Irish calendars at May 25 is a Saint Criumther Cael, whose memory is preserved in the earliest of the surviving calendars, the Martyrology of Tallaght. There he is associated with a locality called Kilmore, literally 'large or great church' which Canon O'Hanlon seeks to place in County Cavan, although as he admits below, he has no firm evidence for doing so, given that Kilmore is too generic a place name:
St. Criumther Cael, of Kilmore, Probably in the County of Cavan.
An entry appears, at the 25th of May, in the Martyrology of Tallagh, regarding this saint. There too, he is said to have been connected with Cill moir, which corresponds with the modern Kilmore. The Bollandists, on the same authority, record his name as Crumtherus Coel, sive Presbyter, at this same date. It is probable, that what follows is only a double entry of this feast, viz., Coelius de Killmor. This place was probably Kilmore, the seat of the bishop's See, in the present county of Cavan; although, this is by no means certain, for many other places in Ireland have received a like name, owing we suppose to the fact of a great church having been erected, in each place so denominated. On this day, likewise, the Martyrology of Donegal mentions the veneration of Cruimther Cael, of Cill-mor.